hematoma

["Randi Lavikoff" <judibn@gate.net>]

I need some quick advice please.  My young gelding panicked in the trailer (to make a long story short), and after the butt bar was up, and his halter was hooked to the trailer tie, he pulled back hard enough to skin his back and sit under the butt bar. Yes, I've read all the loading stuff, anyway, the question now is: my vet was out 2 weeks ago and told me to use DMSO on a lump on his mid-croup (along spinal line), to see if the hematoma that formed, will go down.  His back's fine and I'm eager to start training, again, to do his first 50 this year. Vet said if it doesn't go down, it needs to be drained.  It's been 2 weeks and it's gone down some, but I want to get going on the training and I'm fearful of pressure on the spine.  Should I just go ahead and have it drained now, or wait longer? Thanks ahead. Randi in Florida